Disrupted function of tumor necrosis factor-alpha-stimulated gene 6 blocks cumulus cell-oocyte complex expansion. | Academic Article individual record
abstract

During ovulation, the oocyte and surrounding somatic cumulus cells contained within a specialized, mucoid matrix are released from the ovary. One matrix component, TNF-alpha-stimulated gene 6 (TSG-6), is a hyaluronan binding protein induced in cumulus cells of preovulatory follicles by the LH surge and is decreased in cumulus cells of COX-2 and prostaglandin E2 (PGE2) receptor subtype EP2 null mice that exhibit impaired ovulation and cumulus expansion. To determine if TSG-6 was hormonally induced in cumulus cells in vitro and was functional during the formation of the expanded matrix, we established a cumulus cell-oocyte complex (COC) culture system. This system was used to analyze the effects of FSH, PGE2, EP2 receptor, and selected protein kinase inhibitors on TSG-6 production as well as specific antibodies to the TSG-6 link module on TSG-6 function. We document that TSG-6 message and protein are induced by cAMP/protein kinase A/MAPK signaling pathways and that blocking these cascades prevents expansion and the production of TSG-6. FSH but not PGE2 rescued expansion and production of TSG-6 in the EP2 null COCs, indicating that generation of a cAMP signal is essential. Furthermore, disruption of the functional interactions between TSG-6, inter-alpha trypsin inhibitor, and hyaluronan with specific antibodies severely altered matrix formation and cumulus expansion, as recorded by time-lapse imaging. Collectively, these results indicate that TSG-6 mRNA is induced in cumulus cells in culture by cAMP and that the secreted TSG-6 protein is a key structural component of the mouse COC matrix.

author list (cited authors)
Ochsner, S. A., Day, A. J., Rugg, M. S., Breyer, R. M., Gomer, R. H., & Richards, J. S.
publication date
2003
publisher
published in
keywords
  • Receptors, Prostaglandin E, Ep2 Subtype
  • RNA, Messenger
  • Protein Kinase Inhibitors
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Receptors, Prostaglandin E
  • Dinoprostone
  • Oocytes
  • Mice
  • Female
  • Cells, Cultured
  • Follicle Stimulating Hormone
  • Enzyme Inhibitors
  • Signal Transduction
  • Animals
  • Ovarian Follicle
  • Cell Adhesion Molecules
citation count

104